Grove - Temp&Humi Sensor

This temperature & humidity sensor provides a pre-calibrated digital output

Hello World

Import programSeeed_Grove_Temp_Humidity_Example

Temp and Humidity sensor example. DHT11

Library

Import libraryDHT

Temp and Humidity sensor device driver.

Datasheet

http://www.seeedstudio.com/wiki/Grove-_Temperature_and_Humidity_Sensor

Notes

Features

  • Relative Humidity and temperature measurement
  • Full range temperature compensation Calibrated
  • Digital signal Long term stability
  • Long transmission distance
  • Low power consumption

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Introduction

This page covers the low cost DHT temperature & humidity sensors. These sensors are very basic and slow, but are great for some basic data logging. The DHT sensors are made of two parts, a capacitive humidity sensor and a thermistor. There is also a very basic chip inside that does some analog to digital conversion and spits out a digital signal with the temperature and humidity. The digital signal is fairly easy to read using any microcontroller.

Product Specifications

There are different versions of the DHT sensor, they look a bit similar and have the same pinout, but have different characteristics.

DHT11

  • Power Supply: 3 to 5V DC, 2.5mA max current use during conversion (while requesting data)
  • Operating range: Good for 20-80% humidity readings with 5% accuracy
  • Good for 0-50°C temperature readings ±2°C accuracy
  • No more than 1 Hz sampling rate (once every second)
  • Body size: 15.5mm x 12mm x 5.5mm

DHT22

  • 3 to 5V power and I/O 2.5mA max current use during conversion (while requesting data)
  • Good for 0-100% humidity readings with 2-5% accuracy
  • Good for -40 to 125°C temperature readings ±0.5°C accuracy
  • No more than 0.5 Hz sampling rate (once every 2 seconds)
  • Body size: 15.1mm x 25mm x 7.7mm

The DHT22 is a little more accurate. All sensors have a low sampling rate.

Different names

They come in different packages, breakoutboards:

Wiring / Connectivity

Connection of the SEN11301P or SEN51035P:

/media/uploads/Wimpie/_scaled_wiring.jpg

  • black - GND (Ground)
  • red - VCC (3 to 5V power)
  • white - NC (not connected)
  • yellow - SIG (Signal or data)

Connection of the DHT11 or DHT22:

Don't forget to place a 5K or 4k7 resistor between VCC and the data pin, to act as a medium-strength pull up on the data line.

/media/uploads/Wimpie/dht11_pinout.jpg

  • pin 1 - VCC (3 to 5V power)
  • pin 2 - Data
  • pin 3 - NC (not connected)
  • pin 4 - GND

Example


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